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Home › Saturn › 2002 › L300 › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0102: MAF Sensor Circuit - Low Signal/Frequency › Diagnostic Procedures

Diagnostic Procedures

  1. Turn ignition on, with engine off. Using scan tool, monitor MAF sensor. If voltage reading is less than 0.14 volt, go to next step. If voltage reading is not less than 0.14 volt, problem is intermittent. See DIAGNOSTIC AIDS  .
  2. Turn ignition on, engine off. Check ENG CTRL 1 fuse located in underhood fuse block. Replace as necessary. Disconnect MAF sensor harness connector. MAF sensor is located on air cleaner assembly. Using a DVOM, check voltage in MAF sensor harness connector terminal No. 4 (Gray wire). If voltage reading is 4-6 volts, go to next step. If voltage reading is not 4-6 volts, go to step  4 .
  3. Using a jumper wire, jumper MAF sensor harness connector terminals No. 4 (Gray wire) and No. 5 (Yellow wire). Using scan tool, monitor MAF sensor. If voltage reading is more than 4.8 volts, go to step  5 . If voltage reading is not more than 4.8 volts, go to step  6 .
  4. Using scan tool, monitor MAP SENSOR, APP SENSOR 1 and FTP SENSOR. If all 3 readings are below 0.2 volt, repair short to ground in 5-volt reference "A" circuit (Gary wire). If all 3 readings are not below 0.2 volt, repair open in Gray wire between MAF and ECM.
  5. Connect a test light between ground and MAF sensor harness connector terminal No. 2 (Orange wire). If test light does not illuminate, check for open in circuit between MAF sensor and underhood fuse block. If test light illuminates, check connectors. Repair as necessary. If connectors are okay, replace MAF sensor.
  6. Turn ignition off. Disconnect ECM harness connector J1. Check for continuity between ground and MAF sensor harness connector terminal No. 5 (Yellow wire). Check for continuity between MAF sensor harness connector terminals No. 3 (Purple/White wire) and No. 5 (Yellow wire). If continuity exists on these circuits, go to next step. If continuity does not exist on these circuits, go to step  8 .
  7. Check for short to ground in Yellow wire between MAF sensor and ECM. Check for short between MAF sensor harness connector terminals No. 1 (Tan/Black wire) and No. 3 (Purple/White wire) circuits. Repair as necessary.
  8. Check for open in Yellow wire between MAF sensor and ECM. Repair as necessary. If circuit is okay, check connectors. Repair as necessary. If connectors are okay, replace ECM.
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